code: def demo_liu_hu_lexicon(sentence, plot=False):
      """
      Basic example of sentiment classification using Liu and Hu opinion lexicon.
      This function simply counts the number of positive, negative and neutral words
      in the sentence and classifies it depending on which polarity is more represented.
      Words that do not appear in the lexicon are considered as neutral.
  
      :param sentence: a sentence whose polarity has to be classified.
      :param plot: if True, plot a visual representation of the sentence polarity.
      """
      from nltk.corpus import opinion_lexicon
      from nltk.tokenize import treebank
  
      tokenizer = treebank.TreebankWordTokenizer()
      pos_words = 0
      neg_words = 0
      tokenized_sent = [
          word.lower() for word in tokenizer.tokenize(sentence)
      ]
  
      x = list(range(len(tokenized_sent)))  # x axis for the plot
      y = []
  
      for word in tokenized_sent:
          if word in opinion_lexicon.positive():
              pos_words += 1
              y.append(1)  # positive
          elif word in opinion_lexicon.negative():
              neg_words += 1
              y.append(-1)  # negative
          else:
              y.append(0)  # neutral
  
      if pos_words > neg_words:
          print("Positive")
      elif pos_words < neg_words:
          print("Negative")
      elif pos_words == neg_words:
          print("Neutral")
  
      if plot == True:
          _show_plot(
              x,
              y,
              x_labels=tokenized_sent,
              y_labels=["Negative", "Neutral", "Positive"],
          )
  
imports: import codecs
  import csv
  import json
  import pickle
  import random
  import re
  import sys
  import time
  from copy import deepcopy
  import nltk
  from nltk.corpus import CategorizedPlaintextCorpusReader
  from nltk.data import load
  from nltk.tokenize.casual import EMOTICON_RE
label_desc: Use image node_id 14 for calling a global function with example usage: demo_liu_hu_lexicon(sentence, plot) without return types